“Stand-up” plastic pouches or bottles for holding liquids and other pourable products have become very popular, in part because of the desire to minimize solid waste, in part because of cost, and in part for other reasons. An early stand-up pouch design (U.S. Pat. No. 3,380,646) was devised by the Doyen Brothers in France. That pouch design, including many variants, is still in use today. It is, in fact, the dominant style. The basic Doyen design consists of two flat sheets seamed together along their sides, with a “W” fold running along the bottom. When the pouch is filled, the “W” opens and provides a base on which the pouch can stand. The original Doyen design showed the top being sealed straight across, but subsequent modifications include fitments to allow the pouch to be reclosed after opening.
One difficulty in adding a fitment to a Doyen pouch (and to other pouch designs as well) is that, according to prior art fitment sealing methods, the fitment must be of the “canoe” style to create a joint that can be reliably sealed. The canoe type of fitment is an attempt to minimize the change in direction of pouch material as it comes into contact with the fitment, and in so doing, improve the integrity of the joint where the two sides of the pouch come together at the fitment. However, even the use of a canoe shaped fitment does not completely solve the difficulties in sealing a fitment into a pouch, and a more reliable sealing means is desirable. The present invention provides such a means.
A “canoe” style fitment is characterized by having a sealing surface that includes relatively sharp changes in direction around the sealing periphery so as to permit the pieces of material being sealed to the fitment to approach the fitment sealing surface (laterally) at relatively shallow angles. Or, put another way, as two webs separate to go around the fitment in opposite directions, the angle of divergence is relatively small. Canoe style fitments are illustrated in, e.g., U.S. Pat. No. 5,660,477, U.S. Pat. No. 4,415,085, and U.S. Pat. No. 4,732,299.
Gusseted bottles (but without fitment) have been made in the past (see U.S. Pat. No. 6,193,416, Kawamata et al., U.S. Pat. No. 6,126,315, Ichikawa et al., and U.S. Pat. No. 5,918,984, LaFleur et al.) Obviously, without a fitment, these prior art containers do not have the utility of bottles with fitments.